Method and apparatus for tubal occlusion

ABSTRACT

A device for sterilizing females by occluding the uterotubal junction. The device includes a catheter with a releasable heat generating plug which is used to thermally damage the uterotubal junction and cause it to constrict around the plug, after which the plug is released from the catheter and left in place in the uterotubal junction.

[0001] This application is a continuation of U.S. application Ser. No.10/075,854 filed Feb. 12, 2002, now U.S. Pat. No. 6,726,682, which is acontinuation U.S. application Ser. No. 09/579,976 filed May 26, 2000,now U.S. Pat. No. 6,346,102, which is a continuation of U.S. applicationSer. No. 09/372,394 filed Aug., 10, 1999, now U.S. Pat. No. 6,068,626,which is a continuation of U.S. application Ser. No. 09/063,119 filedApr. 20, 1998, now U.S. Pat. No. 5,954,715, which is acontinuation-in-part of U.S. provisional patent applications 60/048,632filed Jun. 5, 1997 and 60/054,388 filed Jul. 31, 1997.

FIELD OF THE INVENTIONS

[0002] The present invention relates to an apparatus and method forpermanently closing body vessels such as veins, arteries, body tubes,etc. The present invention particularly, though not exclusively, relatesto the occlusion of the female mammalian fallopian tubes. In particular,this invention is directed to a relatively simple surgical procedure forsterilizing human females which may be performed in the physician'soffice.

BACKGROUND OF THE INVENTIONS

[0003] It is often desired or necessary for medical reasons topermanently close body vessels such as veins, arteries, body tubes, etc.Of particular utility is an ability to close the fallopian tubes ofwomen for sterilization purposes.

[0004] One method for sterilization in females is surgical tuballigation, a procedure in which the uterine tubules are tied and cut orclamped through an incision made through the wall of the abdomen. Whendone endoscopically, the pelvic cavity must be pneumatically inflatedusing an inert gas. Aside from injury due to over inflation, numerouscases of the formation of embolisms have been reported. Tubal ligationdone with a laparotomy requires a surgical incision in the abdomenbetween 6 and 12 centimeters long done under general anesthesia. Asidefrom permanent scar formation at the site of incision, there arereported cases of death due to anesthesia complications.

[0005] Other methods for female sterilization have been investigated. Inone technique, investigators have transcervically instilled thesclerosing agent quinacrine into the uterus and fallopian tubes tocreate a permanent closure of the fallopian tubes. Major drawbacks fromthis procedure are the need of repeat applications and a significantlevel of side effects.

[0006] Another technique involves transcervically injecting a curableelastomeric composition such as silicone into the fallopian tubes in anamount sufficient to fill the portion of the oviduct adjacent theuterus. The elastomeric composition is allowed to solidify to therebynonsurgically block the tube. Erb, Method and Apparatus for No-Surgical,Reversible Sterilization of Females, U.S. Pat. No. 3,805,767 (Apr. 23,1974). This technique is time consuming, however, and requires a highlevel of technical skill both for the preparation of the silicone andfor performing the procedure.

[0007] Cohen, et al, Method for Tubal Electroligation, U.S. Pat. No.5,556,396 (Sep. 17, 1996) discloses a method for tubal ligation byproviding an electrically energizable electrode to a fallopian tube. Theelectrode is advanced into the fallopian tube and energized to thermallydamage the fallopian tube, thereby causing enough scarring of thefallopian tube to permanently occlude it. The Cohen patent is herebyincorporated by reference.

[0008] Others have proposed placement of an occlusive wire or coilwithin the fallopian tubes to occlude them. Ton, Endoluminal CoilDelivery System having a mechanical release mechanism, U.S. Pat. No.5,601,600 (Feb. 11, 1997), proposes placement of a Guglielmi detachablecoil (typically used for vascular occlusion) deep within the fallopiantube, past the isthmus. The coil must be delivered into the fallopiantubes with a delivery catheter extending from the uterus into thefallopian tubes.

[0009] Many of the prior art sterilization methods require placement ofan occluding object or device deep within the fallopian tube.Theoretically, the prior art devices make sense. However, the fallopiantubes have proven to be very difficult to cross with any useful device.In the typical human anatomy, catheters and guidewires cannot alwaysnavigate through the fallopian tubes as required by the methods of theprior art.

SUMMARY

[0010] The method of the present invention provides a technique ofsterilization, discussed in greater detail below, which involves thecollapsing of the uterotubal junction and/or fallopian tube around aplug to create total occlusion of the tube. Total occlusion of the tubeprevents male sperm from fertilizing female eggs, thus preventingconception.

[0011] The method comprises, in accordance with the present invention,the steps of: (a) providing an elongated instrument assembly having adistal end portion, (b) inserting the distal end portion of theinstrument assembly through the vagina, across the cervix, and into thepatient's uterotubal junction (uterotubal junction), (c) operating theinstrument assembly to deliver and control radio frequency (RF) energyfrom the instrument, causing the tissue of the uterotubal junction tocollapse on the distal end portion, (d) detaching the distal portion ofthe instrument to create a total seal of the uterotubal junction, (e)removing the remaining portion of the instrument from the patient.

[0012] The method can be modified to permit the sterilization of bothfallopian tubes without removal and replacement of the catheter from theuterus to sterilize the second tube.

[0013] The fact that the tissue destruction is performed outside thefallopian tubes, close to the uterine cavity in the thick portion of theuterotubal junction substantially reduces the risk of bowel injury.Advancement of any device beyond the isthmus of the fallopian tubes orwithin the fallopian tubes is not necessary, although in some casesinsertion into the proximal portion of the fallopian tubes will beaccomplished. No caustic substances come into contact with theperitoneum, obviating unpleasant side effects, and total occlusion ofthe lumen virtually eliminates the risk of ectopic pregnancy.Furthermore, no special technique is required to perform the procedure.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014]FIG. 1 is a partial view of the female reproductive system.

[0015]FIG. 2 is a drawing of the device used to deliver RF power and anoccluding plug to the uterotubal junction.

[0016]FIGS. 2a and 2 b are close up views of the distal segment of thedevice including bipolar electrodes.

[0017]FIG. 3 is a drawing of the device with the distal section placedwithin the uterotubal junction before delivery of RF energy anddetachment of the electrode (plug).

[0018]FIGS. 3a and 3 b are close-up views of the uterotubal junctionbefore and after delivery of RF energy, illustrating detachment of thedistal portion and removal of the remaining portions of the device.

[0019]FIGS. 4-7 describe various electrode designs for use with thedevice.

[0020]FIG. 8 is a side view of a coil shaped distal electrode.

[0021]FIG. 9 is a cross section of the delivery catheter.

[0022]FIG. 10 is a cross section of the electrode plug assemblydisconnected from the transcervical catheter.

[0023]FIG. 11 is a cross section of the occlusion device which useslaser energy and a laser tip to occlude the fallopian tube.

[0024]FIG. 12 illustrates an embodiment of the catheter which usesultrasound energy to occlude the fallopian tube.

[0025]FIG. 13 illustrates an embodiment of the catheter which usescryogenic energy to occlude the fallopian tube.

[0026]FIG. 14 is an overview of the female body illustrating majoraspects of the sterilization method.

DETAILED DESCRIPTION OF THE INVENTIONS

[0027]FIG. 1 shows some of the major elements of the female reproductivesystem. The uterus 2 is an organ of the female pelvis that has the shapeof a pear. It consists of a thick muscular coat, the myometrium 3, acavity having an inner mucosal lining of variable thickness called theendometrium 4, and a cavity referred to as the uterine cavity 5. Thecervix 6 defines the cervical canal 7 which is an inferior opening tothe vagina 8. The fallopian tube 9 is a hollow organ that connects theuterus to the ovary 10. The ovary is the organ that produces one or moreeggs during every cycle of a woman's reproductive life. In the humanfemale reproductive system, there is one uterus, two fallopian tubes andtwo ovaries (under normal conditions). The site where the fallopian tubeand uterus connect is called the uterotubal junction 11. It is a sectionof tubular shape of about 10 mm in length. Its inner diameter in theresting position is less than 1 mm, but when gas or liquid is pushedthrough the uterus and tubes, the diameter of the uterotubal junctionmay stretch up to about 2 mm. The uterotubal junction provides atransition between the uterus and the fallopian tube, and the area oftransition from the chamber of the uterus to the lumen of the uterotubaljunction is referred to as the ostium or cornu (marked with item number12). The area of transition between the ostium and the isthmus 13 of thefallopian tube is referred to as the interstitial portion (marked asitem 14). The ostium, uterotubal junction, interstitial portion, isthmusand fallopian tube are part of a pathway leading from the ovaries to theuterus, and this pathway is sometimes referred to as the uterine tube.

[0028]FIG. 2 shows the main components of the present invention. Thefirst is an elongated tubular segment, better known as a catheter 20,that contains several significant components. The proximal section ofthe catheter contains an electrical connector 21 to connect to an RFgenerator. Also located at the proximal section of the catheter is adeflection handle 22. When the handle is manipulated, the distal section23 of the catheter bends in a relative direction by means of amanipulation wire connected between the handle and distal cathetersection. By operating the actuator means on the handle, the distal tipbends 30 to 180 degrees from straight. (Where the transcervical catheteris used in conjunction with a steerable hysteroscope, the catheteritself need not be steerable.) The detachable electrode plug 24 ismounted on the catheter at the distal end of the catheter, and theproximal actuator 25 is mounted on the handle and connected to adetachment mechanism within the distal tip of the catheter.

[0029] The middle section of the catheter 26, (body), consists of ahollow tubular structure that contains the conductor(s), sensor wires,manipulation device and distal section anchor/release mechanism. Thissection protects the human body from these components and is required todeliver the distal tip portion to the proper location. The middlesection can be manufactured with stainless steel wire braid or windingto improve torque transfer. Improved torque transfer helps assist thedoctor with twisting the handle on the proximal end of the deviceallowing for the torque to transfer to the distal section of the deviceand aid in proper placement of the distal section to the uterotubaljunction. A coating can be applied to the shaft to increase itsradiopacity for X-ray procedures. The coating may include compounds suchas a barium sulfate loaded urethane or Pebax™ manufactured by Atochem.In addition, an echogenic coating can be applied to the shaft toincrease the catheter's visibility during ultrasound imaging. Thiscoating can include trapped air bubbles that provide an echogeniceffect. The catheter shaft may be made with a material loaded with airbubbles as well. Catheter shaft materials can be, but are not limited toPTFE sold under the tradename of Teflon® manufactured by DuPont, ETFE,polyethylene, polypropylene and polyvinylchloride.

[0030]FIG. 2a shows a simple bipolar embodiment for the detachableelectrodes on the distal section 23 of the catheter. The electrode plug24 contains the proximal electrode 27, distal electrode 28, and theinsulator 29 to electrically and thermally insulate the electrodes, theanchor/release mechanism 30 for the electrode and a temperature sensor.It also contains a soft catheter portion 34 to allow deflection when theproximal handle is manipulated. One conductor wire is attached to thedistal electrode and a second conductor wire is attached to the proximalelectrode. The length of the conductors is contained within the catheterbody to isolate it from the patient. The conductors are coated with anelectrically insulative material. The proximal end of each conductor isattached to the electrical connector 21. The electrical connector isthen connected to an RF generator.

[0031]FIG. 2b illustrates another embodiment for the bipolar electrodeplug 24. The electrode assembly includes two hot electrodes 35 d and 35p, and two ground electrodes 36 d and 36 p mounted on the insertionportion 37 of the electrode plug 24. The insertion portion comprises theinsulator 29 and the electrodes. The attachment mechanism 30 attaches tothe soft catheter portion 34, and is housed within the proximal sectionof the electrode plug 24. The proximal section of the plug may beprovided with a larger diameter cross section than the insertionportion, in order to form a shoulder or flange type surface 38 whichwill serve to limit insertion of the plug and prevent insertion into thefallopian tubes.

[0032] The distal electrodes can be made from any electricallyconductive material such as stainless steel, copper, Elgiloy™, MP35N,platinum, titanium, nitinol and various other materials and alloys. Thesurface of the distal electrode can be covered or finished with a porousdesign to encourage fibroblast and/or tissue ingrowth. Tissue ingrowth(possibly referred to as scar formation) around the electrode insures apermanent seal of the fallopian tube. Different shape configurations andundercuts can also be incorporated into the electrode design to insure apermanent seal of the fallopian tube. Various embodiments of bipolar andmonopolar plugs may be adapted for use. For a monopolar device, there isonly one electrode on the distal section of the catheter. A dispersiveelectrode placed on the patient's exterior creates the current path forthe monopolar device. While this is unsuitable for devices attemptingthermal damage of the thin-walled fallopian tube, it should be suitablefor the thick portion of the uterotubal junction. The insulator 29 canbe made from any of the thermal and electrically insulative engineeringmaterials such as ceramic, polyetheretherketone, Ultem™ manufactured byGeneral Electric, phenolic, epoxy, Pebax™ and PTFE. The surface of theinsulator can be covered or finished with a porous design to encouragefibroblast ingrowth. The insulator can be manufactured from porousexpandable material such as Teflon. Use of expanded PTFE encouragestissue ingrowth and/or scar formation around the electrode insuring apermanent seal and preventing plug migration over time. The insulatormay be a coating applied over a conductive material.

[0033] The insulator can also be made from any of the bioresorbable orbioerodible materials such as polyglycolic acid (PGA), polylactic acid(PLA), polydioxanone (PDS), or any combination of them. The insulatormaterial can also be attached to the distal section of the plug toencourage tissue ingrowth and/or scar formation distally from the plugin the fallopian tube.

[0034] The proximal electrode 27 can be made from any electricallyconductive material such as stainless steel, copper, Elgiloy™, MP35N,platinum, titanium, or nitinol or other alloys. The proximal electrodecan be larger than the distal electrode. This creates a higher currentdensity in the tissue adjacent to the distal electrode and insulator, sothat collapse of the fallopian tube is more pronounced in the insulatorand distal electrode portion.

[0035] The distal portion can also contain a temperature sensing devicesuch as a thermocouple or thermistor. The sensor is connected forfeedback to a control circuit that modulates RF power applied to theelectrodes according to the signal received from the temperature sensor.The control circuit compares the signal from the temperature sensor to aset value and modulates the RF power applied to the electrode inaccordance with the set value. A predetermined temperature setting canalso be used to stop RF power delivery to the electrode. In this wayoverheating of the uterotubal junction can be prevented and thepossibility of bowel perforation minimized.

[0036] The procedure can be done under x-ray guidance, sonographically,hysteroscopically, or blindly. The procedure can be done under generaland local anesthesia or general anesthesia only or local anesthesiaonly, with the latter preferred. The device is inserted into the bodynon-invasively: through the vagina, through the cervix into the uterus.This device can be inserted into another device such as a hysteroscopealready positioned across the cervix.

[0037] By manipulating the proximal handle, the distal segment can bedeflected to assist in proper positioning of the distal electrode withinthe uterotubal junction or fallopian tube ostium or fallopian tube.

[0038] Impedance measurements are taken from the tip electrode(s) toassist with proper positioning. For a bipolar device design, in thepresence of an electrolyte distention media (such as saline solution),impedance will increase when the electrode is positioned properly withinthe uterotubal junction. It has been shown that this rise in currentresistance is due in part to the current path moving from theelectrically conductive media into the relatively higher resistanttissue within the uterotubal junction.

[0039] For a bipolar device in the presence of a non-electrolytedistention media (such as sorbitol), impedance will decrease when theelectrode is positioned properly within the uterotubal junction. It hasbeen shown that this decrease in current resistance is due in part tothe current path moving from the non-electrically conductive media intothe relatively lower resistant tissue within the uterotubal junction.

[0040] For monopolar electrodes, in the presence of a non-electrolyticdistention media, the impedance will decrease when the electrode ispositioned properly within the uterotubal junction. It has been shownthat this decrease in current resistance is due in part to the currentpath moving from the non-electrically conductive media into therelatively lower resistant tissue within the uterotubal junction.Impedance monitoring can be accomplished through the electrode plug inthe RF embodiments, and it can be accomplished with the addition ofimpedance sensing electrodes in the laser and ultrasound embodiments.

[0041] It is also possible with the current device to deliver a localanesthesia to the uterotubal junction before the delivery of RF, laseror ultrasound energy. This will prevent any discomfort to the patientduring the procedure. It can be delivered in a liquid, gel, paste orpill form directly to the site. It can also be loaded into theelectrode(s), laser hot tip, or ultrasound heating element, or intoother parts of the device such as the insulating portions of the RFelectrode assembly.

[0042] When the electrode plug is in position, controlled delivery of RFcurrent to the electrode(s) causes constriction of the vessel around thedistal electrode and insulator. Temperature and/or impedance monitoringcan be used to control or terminate RF current delivery to theelectrode. For temperature, the control circuit compares the signal fromthe temperature sensor to a set value and modulates the RF power appliedto the electrode in accordance with the set value. A predeterminedtemperature setting can also be used to stop RF power delivery to theelectrode. For impedance, the control circuit compares the signal fromthe electrode(s) to a set value and modulates the RF power applied tothe electrode(s) in accordance with the set value. A predeterminedimpedance setting can also be used to stop RF power delivery to theelectrode.

[0043]FIGS. 3 through 3b illustrate the procedure. FIG. 3 shows theuterus and the structures of FIG. 1, including the uterus 2, cervix 6,vagina 8, fallopian tubes 9, uterotubal junction 11, the interstitialportion 14 and the ostium 12. The catheter 20 has been inserted throughthe vagina and across the cervix to the area of the ostium. Theelectrode plug 24 has been advanced into the uterotubal junction 11,until the shoulder of the plug meets the junction and inhibits furtherinsertion (the surgeon will feel increased resistance to advancement,and will be able to visually observe impact of the shoulder). Note thatelectrode plug 24 is inserted into a fairly thick area of the uterotubaljunction 11 and the interstitial portion, and has not entered theisthmus 13 or the thin walled portion of the fallopian tube 9. Insertiononly into the extra-fallopian length of the lumen will prevent thepossibility of burning or puncturing a hole in the fallopian tube andsurrounding structures. FIG. 3a shows the electrode plug 24 mounted onthe catheter distal tip 23 and inserted into the uterotubal junction 11before heating of the plug and surrounding tissue with RF energy. Thesurrounding tissue of the uterotubal junction has been thermally injuredand has swollen around the plug and into the gaps between theelectrodes. When sufficient occlusion has been accomplished, the distalelectrode and insulator are detached from the body of the catheter. Thisis accomplished by operating the proximal actuator illustrated in FIG.2. FIG. 3b illustrates the plug after separation of the plug from theremainder of the device. The electrode plug 24, including the electrodes36d, 36 p, 35 d, and 35 p, and the insulator 29, remain within theuterotubal junction. The surrounding tissue will heal in this condition,essentially surrounding and encapsulating the electrode plug to create amechanical lock on the plug. The electrode plug may be made in otherembodiments which permit detachment of the distal electrode section fromthe remainder of the plug. In this case, a distal electrode andinsulator remain in place while the remaining portion of the catheter,including the proximal electrodes, are removed from the body. In yetanother embodiment of the invention, there are several electrodesattached to the distal catheter to allow the physician to occlude bothfallopian tubes without withdrawal of the device. The electrode(s) andinsulator are designed to encourage fibroblast ingrowth to create ahermetic seal and prevent electrode migration.

[0044]FIGS. 4a through 4 d illustrate various shapes for electrodes inthe simplest embodiment of the device. FIG. 4a is a cylindrical plugwith a ball point 39 at the distal end of the plug. FIG. 4b is acylindrical plug with a bullet point 40 at the distal end of the plug.FIG. 4c is a cylindrical plug with a flat cylinder top 41 at the distalend of the plug. FIG. 4d is a frustoconical plug with the small end 42at the proximal end of the plug (it can be reversed). FIGS. 5a-5 cillustrate embodiments of the electrode plug which provide formechanical interlocking relationship between the shrunken uterotubaljunction and the electrode. FIG. 5a shows a pawn shaped electrode. FIG.5b shows a barbell shaped electrode, with globular bells 43 on eitherend of the electrode plug, separated by the insulator portion 29. FIG.5c illustrated a barbell shaped electrode with an additional bell 44between the bells at either end. FIG. 5d illustrates a multi-flangedelectrode assembly, with several flanges 45 extending outwardly from theinsulator portion 29. FIGS. 6a through 6 c illustrate various forms forthe proximal end of the electrode plug, making up the proximal shoulder38. FIG. 6a illustrates a simple flange 46 on the proximal end of theelectrode assembly 24, while FIG. 6b shows a mushroom shaped flange 47,and FIG. 6c illustrates a contoured flange 48. These shapes may beapplied to the proximal end (the uteral side of the plug) in order tolimit the insertion of the plug into the fallopian tube. FIG. 7 shows aplug having a screw thread 49 outer contour.

[0045]FIG. 8 illustrates a coil-shape configuration of the distalelectrode plug. By manufacturing the electrically conductive materialinto a wire or strip, it is possible to wind the material over theinsulative material to form a coiled electrode. A bipolar coiled plug ismade possible by incorporating two separate wires parallel to each otheralong the coiled length. Thus FIG. 8 includes a helical ground electrode50 and a helical hot electrode 51 coiled in parallel about insulatedplug 52 to form the entire plug assembly 53. The winding pitch or anglebetween wire and the insulative material being wound on can vary throughthe plug. By varying the pitch angle, it is possible to create differentcurrent density fields for the plug. The pitch can vary from 0°(parallel to the plug's major axis) to 90° (perpendicular to the plug'smajor axis). In one embodiment, the pitch remains at 0° for the lengthof the plug and is not wound at all.

[0046]FIGS. 9 and 10 show cross sections of the delivery catheter withmechanism for delivering energy to the heating tip and disconnecting thetip from the remainder of the catheter. Transcervical catheter 20 isshown housed within the working channel of a hysteroscope 54. The distaltip 23 of the transcervical catheter 20 houses the electrode assembly24. The electrode plug 24 is a bipolar electrode plug, with a centralbore 55 which receives the central conductor assembly 56. The centralconductor assembly comprises the necessary wiring to carry energy to theelectrode assembly. The electrode assembly includes a electrode plug 57with a mating assembly 58 at its proximal end 59. The proximal end ofthe plug is flared, with shoulders 38, designed to ensure that theelectrode is not inserted beyond the uterotubal junction. Groundelectrodes 36 d and 36 p and hot electrodes 35 d and 35 p providebipolar RF energy to any tissue outside the plug. The electrodes areconnected to the remainder of the catheter through electrical contacts60, and these contacts are further connected to ground wires and hotwires coiled onto the central conductor assembly 56. The mating assembly58 includes a receiving bore 63 for receiving the central conductorassembly. The distal end of the transcervical catheter likewise has areceiving bore 64 for receiving the spring loaded tangs or detentes 65which are biased toward the center of the device, but held in radiallyexpanded condition by the thickness of the central conductor assembly56. The tangs 65 extend into matching receiving holes 66 in the distalend of the insertion catheter 20. The electrical ground wires and hotwires are connected to the RF generator which is outside the body,connected to the proximal end of the transcervical catheter.

[0047] In use, as discussed above, the hysteroscope and transcervicalcatheter are inserted into the uterus through the cervix. Using thehysteroscope, the physician can locate the ostium of the fallopian tube,which corresponds to the uterotubal junction. The physician advances thetranscervical catheter out of the hysteroscope, and inserts the pluginto the uterotubal junction until the shoulders of the plug are firmlyseated in the uterotubal junction. Electrical energy is applied throughone or more of the electrodes, grounded through the ground electrodes.When the uterotubal junction has been thermally damaged, it collapsesand constricts about the electrode plug. The outer surface of theelectrode plug is irregular, allowing mechanical interlock between theuterotubal junction and the plug when the plug constricts over the plug.After heating, the central conductor assembly 56 is pulled proximallywhile the catheter 20 is held in place. When the central conductorassembly 56 is pulled distally to the point where it clears the tangs,the tangs resiliently rebound to the center of the catheter and fall outof the receiving holes 66, as illustrated in FIG. 10. Should anyresistance be encountered, the shoulder 67 on the transition of thecentral conductor assembly 56 may be used to push gently on theelectrode plug while gentle force is applied to the catheter. Thedeployed plug is left in place to provide permanent occlusion of thefallopian tube. (The process is repeated for each fallopian tube.)

[0048] The RF energy may be supplied by any one of numerous RF energygenerators available commercially. Although RF energy is currentlypreferred, microwave energy may also be used, and microwave energygenerators suitable for use include such devices as the Prostatronmicrowave generator currently used for application of microwave energyto the prostate. Microwave power in the frequency of about 100 MHz to14,000 MHz will also provide sufficient thermal damage to the fallopiantube to initiate collapse and constriction around the electrode.

[0049]FIG. 11 illustrates an embodiment of the catheter which uses laserlight, rather than RF energy, to provide the heat necessary to thermallydamage the fallopian tubes and cause them to constrict. In addition tothe parts already discussed in relation to the RF embodiment, the laserdevice shown in FIG. 11 includes a laser light source (not shown), acentral conductor 56 comprising fiber optic fiber 70 capable ofdelivering laser light from the laser source to the tip of theelectrode, and a laser heating tip 71 disposed at the distal end of thecatheter. The fiber optic fiber is releasably attached to the heatingtip with a mechanism such as the releasable detentes described above.(Other mechanisms may include press fitting the fiber optic into areceiving bore in the heating tip so that it may be pulled out of thetip after heating, maintaining the tip in place with force from thecatheter outer tube. The optical fiber may also be glued or melted intothe tip, and simply snipped with endoscopic cutters after heating.) Forthis application, laser light sources are commercially available for avariety of other purposes, and these may be readily adapted for use insupplying heating light for the fallopian tubes. The heating tip 71 is aplug of silicone, bioglass or other transparent tip suitable for laserheating, and in this case it is cylindrical. The fiber optic is aimed atthe proximal end of a necked down detente holding pin 73, which isinserted into the receiving bore of the heating tip. The distal end ofthe fiber optic fiber and the distal end of the receiving bore arehighly polished to permit maximum transmittance of laser light into thetip. A reflective surface 74 is applied to the distal face of the tip toreflect laser light that reaches the distal face back into the plug. Theplug is loaded with dispersive particles (silica, alumina or titania)which serve to disperse the laser energy throughout the plug and convertthe energy into heat. When the plug is heated in this manner, it heatsthe surrounding uterotubal junction tissue to affect the thermal damagewhich is desirable in the sterilization method. Laser light sources andpower ranges typically used for such applications of laser thermaltreatment are expected to be safe and sufficient for use in applicationto the uterotubal junction.

[0050]FIG. 12 illustrates an embodiment of the catheter which usesultrasound energy, rather than RF energy, to provide the heat necessaryto thermally damage the fallopian tubes and cause them to constrict.FIG. 12 shows the tip of the device, including the plug 75, thetranscervical catheter 76, the piezoelectric crystal 77 and electricalconductors 78. The plug is connected to the catheter outer tube 72 ofthe catheter with a release mechanism similar to that shown in theearlier figures. The coupling element 79 sonically couples thetransducer to the plug, and also mechanically couples the transducer tothe plug. The coupling element also includes a small diameter distalextension which fits into the bore of the plug during delivery andheating, and permits release of the tangs 65 when the central conductoris pulled proximally and the wide proximal portion 80 clears the tangs.Excitation of the piezoelectric crystal with electrical impulsesdelivered through the wires will cause the plug 75 and surroundingtissue to heat up, thereby causing the thermal damage to the uterotubaljunction desired to cause collapse around the plug. Again, when theuterotubal junction collapses around the plug, the plug can bedisconnected from the rest of the transcervical catheter and left inplace. Ultrasound energy in the range of 10 KHz to 4 MHz may be appliedto effect thermal damage.

[0051]FIG. 13 illustrates an embodiment of the catheter which usescryogenic cooling, rather than heating, to provide the thermal damagenecessary to cause the fallopian tubes to constrict. FIG. 13 shows thetip of the device, including the detachable cryogenic plug 84 mounted onthe tip of the transcervical catheter 20. The detachable plug in thisinstance comprises the tip of a cryosurgical probe of the type that usesliquid nitrogen. Cooling of the plug is accomplished by cryogeniccooling of the jacket 85 which fits closely within the plug. The cryogensupply line 86 communicates with the annular lumen 87 formed between thejacket 85 and the supply line. The supply line includes a port 88 at thedistal tip, to distribute cryogenic fluid into the jacket. Liquidnitrogen or other cryogen is supplied to the probe through the supplyline, and exhausts out the annular lumen and the gas return line 89.After application of cryogenic cooling, the gas line is pulledproximally until the jacket clears the tangs 65 of the releasemechanism, at which point the tangs release the catheter 20 and the plugis left in place.

[0052] Another embodiment of the device is one which accomplishesconductive and convective heating through the plug to accomplish thesame results. There are several other ways to heat the fallopian tubethrough the plug by conductive and convective techniques. For example,AC or DC current can be delivered directly through the plug to createresistive heating of the plug which in turn generates a hot surface onthe plug. Another possible technique is the delivery of a hot gas or hotliquid through channels of the catheter to the plug.

[0053] A plug could be designed with a resistive element placed with theplug to heat the plug and its surface. Heat would be transferred to theuterotubal junction by conduction and/or convection. Conduction of heatfrom the plug surface to the uterotubal junction is accomplished byplacing the plug in direct contact with the uterotubal junction.Convection of heat from the plug surface to the uterotubal junction isaccomplished by transfer of heat from the plug surface to fluids in thearea of the plug such as body fluids or artificial liquids, and thisfluid in turn transfers heat to the uterotubal junction

[0054]FIG. 14 illustrates the overall method of using the devicesdescribed in this patent. The patient 1 lays on an operating table 90,in position similar to that used for a gynecology exam, providing accessto the vagina 8. Access to the cervix 6 and uterus 2 is facilitated byinsertion and opening of the speculum 91, which is locked to theoperating table 90 with clamping mechanism 92. The physician inserts thehysteroscope 54 to find and inspect the opening into the fallopian tubes(called the ostium), and then inserts the transcervical catheter 20 andadvances the transcervical catheter until the plug is seated in theostium of the fallopian tube. When the plug is properly positioned, thephysician will then use the catheter locking mechanism 93 (theillustrated locking mechanism is a set screw installed on thehysteroscope access port 94) to fix the transcervical catheter in placeand prevent accidental removal of the plug during the procedure orduring release of the plug. The speculum clamp and catheter lockingmechanism form a locking jig which includes one clamp for fixing thescope to the operating table and a second clamp for securely holding theproximal end of the transcervical catheter. (With the transcervicalcatheter locked in place in this manner, the physician may safely applyenergy to the releasable tip without fear of inadvertently pulling theplug uterotubal junction and misapplying the required energy.) Thephysician then applies energy sufficient to cause the uterotubaljunction to collapse about the catheter tip. After collapse andconstriction has been confirmed (this may be done visually through thehysteroscope, or by comparison of electrode impedance in the RFembodiments), the physician will hold the outer body of thetranscervical catheter firmly and pull the central conductor from theplug. (Again, with the transcervical catheter locked in place, thephysician may safely withdraw the central conductor from the plugwithout fear of inadvertently pulling the plug from the thermallydamaged uterotubal junction.) With the central conductor removed fromthe plug, the catheter should fall away from the plug. The physicianwill then remove the catheter. For complete sterilization, the physicianwill then repeat the procedure on the other side of the uterus. (Variousembodiments of locking mechanisms may be used, and will suffice toimmobilize the catheter in relation to the patient by any locking means.Where a hysteroscope is not used, or is provided without the lockingscrew as illustrated, it will suffice to lock the catheter to thespeculum. It will also be sufficient to lock the speculum to thehysteroscope and use the friction between the working channel of thescope and the catheter to stabilize the catheter and avoid excessivemovement of the purse. The number of possible locking mechanismembodiments is vast.)

[0055] Immediately after delivery of the RF energy to the targetedtissue, several stages of tissue response will occur in the healthyfemale. First, the damaged tissue will undergo an acute inflammatoryresponse. In this stage, serum and white blood cells exit from the bloodvessels near the tissue and move into the interstitial space between thecells. This process is called edema. This process is accompanied by therelease of products from the mast cells, which increase the vascularpermeability to serum and white blood cells, increasing the edema. Giantcells called macrophages then move into the damaged tissue and startdigesting the thermally damaged cells.

[0056] The next stage of response is the healing stage, in which repairmechanisms take place to restore the uterotubal junction to its originalcondition. In this stage, cytokines and other products released by themast cells stimulate the fibroblasts of the conjunctive tissue (underthe endosalpinx) which duplicate and migrate into the area of thedestroyed tissue. The fibroblasts then produce a matrix of gel likematerial and fibers in which the fibroblasts proliferate. This processis called colonization, and continues until the entire damaged area isfilled with fibroblasts. The blood vessels in the injured area form budswhich grow into the new fibroblast matrix and revascularize the newlyformed tissue.

[0057] The plug which is left behind in the uterotubal junction will bemaintained in place by the constrictive action of the damaged tissue,during the healing process. As an aid to long term retention, the plugis porous to a degree which allows endothelial tissue and/or conjunctivetissue of the uterotubal junction to grow into the pores of the plug.The presence of the artificial matrix such as the plug provides anopportunity for the fibroblasts to grow into the plug and favorsocclusion of the fallopian tube in the area of the plug. To enhancetissue adhesion to the plug, each of the plugs illustrated above may bemade of a porous material (metal, glass, ceramic or other material) withpores ranging from about 1-400 microns. The pores may be natural to thematerial, or they may be manufactured into the material. (For example,metal plugs with pores may be manufactured as reticulated or foamedmetals according to known techniques.)

[0058] Tissue in-growth can be promoted by application of in-growthpromoting compounds such P15 or HEP III to the porous plug. Such agentsthat promote either the attachment of cells to the plug or the cellulargrowth deep into the pores and surface features (nooks and crannies) ofthe plug. Examples of such agents include protein coatings such ascollagen, fibronectin, and transforming growth factor beta, or asynthetic polypeptide coatings such as P15(Gly-Thr-Pro-Gly-Pro-Gln-GLy-Ile-Ala-Gly-Gln-Arg-Gly-Val-Val) or HEP III(GLy-Glu-Phe-Tyr-Phe-Asp-Leu-Arg-Leu-Lys-Gly-Asp-Lys), The manufactureof these compounds is well described in Bhatnagar, Synthetic CompoundsAnd Compositions With Enhanced Cell Binding, U.S. Pat. No. 5,635,482(Jun. 3, 1997) and Tsilibary, Prosthetic Devices Coated With APolypeptide With A Type IV Collagen Activity, U.S. Pat. No. 5,152,784(Oct. 6, 1992). Coating of the device by these proteins or polypeptidescan be accomplished by dipping the plug into a solution or liquidsuspension of the coating. This may be done immediately beforeimplanting the plugs into the uterotubal junction, merely by dipping orglomming P15 suspension onto the plug. The coating may also be appliedduring manufacture using dipping and coating techniques commerciallyavailable from such companies as Peptide Innovations, Inc. ofSouthfield, Mich. Additionally, the in-growth promoting compound may beinjected to the vicinity of the plug after the plug has been implantedor before implantation. Although heat will be generated in the vicinityof the plug, the in-growth promoting compound is not damaged.

[0059] The P15 compound appears to permit direct attachment of newendothelial cells to the plug material, and the endothelial cells arefurther attached to the uterotubal junction, thus securing the plug inplace. The compound also appears to encourage endothelial growthsufficient to create a matrix of endothelial cells which is mechanicallyintermingled with the porous structure of the plug.

[0060] The power requirements and length of time that energy must beapplied to the uterotubal junction are modest, on the order of a fewwatts of power for several seconds. In initial experiments, a range ofpower and application time proved useful in constricting body tissue. Inone experiment, we tested the effects of RF energy on bovine coronaryarteries. A catheter was placed within the arterial structure and 10watts of RF energy were delivered to the distal electrode for about 10seconds. The artery constricted tightly on the catheter tip electrode.The diameter of the artery was measured at 0.064 inches with about 3 cmof the artery cut out of the myocardium. The experiment was repeated andthe catheter was slowly dragged through the artery while the RF energywas delivered. The artery and its surrounding tissue were cut in halffor observation. The RF energy delivered through the electrodeconstricted and closed the artery.

[0061] In a second experiment, we tested the effect of RF energy appliedthrough a catheter on a uterus and fallopian tubes of a large sow (500lbs.). We separated the uterotubal junction, fallopian tubes and ovariesfrom the reproductive system. We then placed a 7F steerableelectrophysiology catheter with a 4 mm long tip through the uteral endinto the fallopian tube. We applied 5 watts of power for 15 seconds.This caused necrosis, tissue discoloration and occlusion at theelectrode position. A small amount of force was required to remove theelectrode.

[0062] In a third test, we tested the seal provided by a removableelectrode after RF treatment. We inserted a dumbbell-shaped electrodeinto the uterotubal junction of a large sow, and applied ten watts ofenergy for 20 seconds. This caused necrosis, tissue discoloration andocclusion at the electrode position. A tensile tester was then attachedto the electrode wire and pulled up to a force of 0.5 pounds withoutdislodging the electrode. With the electrode left in place, we placed asyringe needle into the distal section of the fallopian tubes and tiedoff the fallopian tubes around the needle with suture. We then attachedan ACS PTCA indeflator containing diluted blue dye to the needle andapplied pressure at about 20 psi for 15 minutes. We then attached asyringe of pure dye to the needle and applied a relatively high amountof pressure for 2 minutes. Blue dye was observed dripping out of thedistal section of the fallopian tubes, through the tied off segmentaround the needle. None of the dye leaked past the plug into the uterus.

[0063] Variations in the devices presented above are expected to arisein practice of the inventions. For example, the optimal power settingsand time for application of energy will most likely be refined withbroader experience with the devices. It is expected that additionalmaterial for the plug will be developed and employed in the practice ofthe inventions. It is also expected that new in-growth promotingcompounds will be discovered and applied in the practice of inventions.The plug may also be designed to be removed at a later date, either byremoving a central core or by collapsing in on its self.

[0064] Finally, although the inventive methods and devices have beendescribed in the environment of human sterilization, they may be appliedin numerous animals for which sterilization is often desired. Thus,while the preferred embodiments of the devices and methods have beendescribed in reference to the environment in which they were developed,they are merely illustrative of the principles of the inventions. Otherembodiments and configurations may be devised without departing from thespirit of the inventions and the scope of the appended claims.

We claim:
 1. A device for sterilization of a female comprising: acatheter having a distal end adapted for insertion through the vaginaand cervical canal and into the uterine tube of the female; a detachablenon-expandable plug releasably mounted to the distal end of thecatheter; means for applying energy to the uterine tube, through theplug; and a release mechanism capable of releasing the non-expandableplug from the distal end of the catheter; wherein said plug isconfigured to fit entirely within the uterine tube and wherein saidelectrode is capable of applying energy to the plug sufficient to causedamage to the uterine tube.
 2. The device of claim 1 wherein the plugcomprises an insulator and an electrode mounted in the insulator, andthe means for applying energy comprises a source of electrical energycoupled to the electrode.
 3. The device of claim 1 wherein the plugcomprises a resistive heating element, and the means for applying energycomprises a source of electrical energy coupled to the resistive heatingelement.
 4. The device of claim 1 wherein the plug comprises a laserheating tip, and the means for applying energy comprises a source oflaser energy coupled to the electrode.
 5. The device of claim 1 whereinthe plug comprises a piezoelectric crystal, and the means for applyingenergy comprises a source of electrical energy coupled to the crystal.6. A device for sterilization of a female comprising: a catheter havinga distal end adapted for insertion through the vagina and cervical canaland into the uterotubal junction of the female; a detachablenon-expandable plug releasably mounted to the distal end of thecatheter; means for applying energy to the uterotubal junction, throughthe plug; and a release mechanism capable of releasing thenon-expandable plug from the distal end of the catheter; wherein saidplug is configured to fit entirely within the uterotubal junction andwherein said electrode is capable of applying energy to the plugsufficient to cause damage to the uterotubal junction.
 7. The device ofclaim 6 wherein the plug comprises an insulator and an electrode mountedin the insulator, and the means for applying energy comprises a sourceof electrical energy coupled to the electrode.
 8. The device of claim 6wherein the plug comprises a resistive heating element, and the meansfor applying energy comprises a source of electrical energy coupled tothe resistive heating element.
 9. The device of claim 6 wherein the plugcomprises a laser heating tip, and the means for applying energycomprises a source of laser energy coupled to the electrode.
 10. Thedevice of claim 6 wherein the plug comprises a piezoelectric crystal,and the means for applying energy comprises a source of electricalenergy coupled to the crystal.
 11. A device for sterilization of afemale comprising: a catheter having a distal end adapted for insertionthrough the vagina and cervical canal and into the uterus of the female;a detachable non-expandable plug with at least one electrode mounted onthe plug wherein the plug is releasably mounted to the distal end of thecatheter; and a release mechanism capable of releasing thenon-expandable plug from the distal end of the catheter; wherein saidplug is configured to fit within the uterotubal junction and whereinsaid electrode is capable of applying energy to the plug sufficient tocause damage to the uterotubal junction.
 12. The device of claim 11wherein the release mechanism is comprised of: at least one tangextending from the plug into the catheter, said tang being resilientlybiased toward the center of the catheter; at least one receiving holedisposed within the catheter near the distal end of the catheter forreceiving the tang to lock the plug to the catheter; a slidable coreextending from the proximal end of the catheter to the distal end of thecatheter, said slidable core having a distal end with a first diameter,said slidable core disposed within the catheter and extending intoobstructing relationship with the tang, thereby preventing the tang fromresiliently bending toward the center of the catheter when obstructed bythe core and maintaining the tang engaged with the receiving hole, saidslidable core being slidable distally to move out of obstructingrelationship with the tang; a bore within the plug, said bore having afirst diameter; and a distally extending segment on the core, saiddistally extending segment extending from the distal end and having asecond diameter smaller than the first diameter of the distal end, saidsecond diameter sufficient to permit the distally extending segment tofit within the bore of the electrode.
 13. The device of claim 11 wherein the plug is comprised of porous material.
 14. The device of claim 11wherein the plug has at least one electrode operable as a monopolarelectrode.
 15. The device of claim 11 wherein the plug comprises atleast two electrodes operable as bipolar electrodes.
 16. The device ofclaim 11 further comprising a power source capable of applying RF energyto the plug sufficient to cause damage to the uterotubal junction. 17.The device of claim 11 wherein the release mechanism is capable oftransferring RF energy to the electrode.
 18. The device of claim 11wherein the plug further comprises an in-growth promoting compound. 19.A device for sterilization of a female comprising: a catheter having adetachable non-expanding plug releasably mounted on the distal end ofthe catheter; and a release mechanism capable of releasing the plug fromthe distal end of the catheter; wherein said plug is configured to fitwithin the uterotubal junction and wherein said electrode is capable ofapplying energy to the plug sufficient to cause damage to the uterotubaljunction; wherein the release mechanism comprises at least one tangextending from the plug into the catheter, said tang being resilientlybiased toward the center of the catheter; at least one receiving holedisposed within the catheter near the distal end of the catheter forreceiving the tang to lock the plug to the catheter; a slidable coreextending from the proximal end of the catheter to the distal end of thecatheter, said slidable core having a distal end with a first diameter,said slidable core disposed within the catheter and extending intoobstructing relationship with the tang, thereby preventing the tang fromresiliently bending toward the center of the catheter when obstructed bythe core and maintaining the tang engaged with the receiving hole, saidslidable core being slidable distally to move out of obstructingrelationship with the tang; a bore within the plug, said bore having afirst diameter; and a distally extending segment on the core, saiddistally extending segment extending from the distal end and having asecond diameter smaller than he first diameter of the distal end, saidsecond diameter sufficient to permit the distally extending segment tofit within the bore of the electrode.
 20. The device of claim 19 furthercomprising: a bore within the plug; at least one electrical contactextending from at least one of the electrodes, through the plug towardsthe bore of the plug, and adapted to be in electrical contact with thecore; wherein the distal end of the core is adapted for insertion intothe bore and into the electrical contact with the at least oneelectrical contact.
 21. The device of claim 20 where in the plug iscomprised of porous material.
 22. The device of claim 20 wherein theplug has at least one electrode operable as a monopolar electrode. 23.The device of claim 20 wherein the plug comprises at least twoelectrodes operable as bipolar electrodes.
 24. The device of claim 20further comprising a power source capable of applying RF energy to theplug sufficient to cause damage to the uterotubal junction.
 25. Thedevice of claim 20 wherein the release mechanism is capable oftransferring RF energy to the electrode.
 26. The device of claim 20wherein the plug further comprises an in-growth promoting compound.